1. Field of Invention
The invention relates to an ink-jet recording apparatus that performs recording by ejecting an ink droplet, and more particularly, to the ink-jet recording apparatus that has a recovery mechanism for ink ejection.
2. Description of Related Art
A known recording apparatus, such as a printer, that performs printing on a recording medium, such as a sheet of paper and an overhead transparency film, includes a print head of, for example, an ink-jet type, a dot impact type, or a thermal transfer type. Specially, the ink-jet print head performs high-speed and high-quality printing with a low noise level, without having complicated structures.
In the ink-jet head, a plurality of nozzles that eject ink are formed. In order to perform high-quality printing using the ink-jet print head, ink in and around the nozzles needs to be maintained in appropriate conditions. More specifically, when the ink is placed in inappropriate conditions where, for example, the ink contains air bubbles or dirt or other contaminants, or is dried and becomes viscous due to evaporation of the ink solvent, the ink may not be ejected or may be inappropriately ejected. In such cases, a recovery operation to obtain proper ink ejection is performed to clear the inappropriate conditions of the ink or to eliminate the causes of the ink ejection failure.
In order to perform the recovery operation, some ink-jet recording apparatuses include a cap that covers an ejection surface of the ink-jet print head where openings of the nozzles are provided, a suction pump that sucks ink from the ink-jet print head through a tube connected to the cap, by applying a suction force to the cap, and a waste ink reservoir that receives ink sucked by the suction pump. The suction pump is driven when the cap covers the nozzle ejection surface, to generate a negative pressure in the cap, thereby forcibly discharging ink from the ink-jet print head. Thus, causes of the ink ejection failure are eliminated.
The ink received in the cap by the recovery operation is required to be completely discharged from the cap, through the suction pump, to the waste ink reservoir, by the application of the suction force. However, the ink may not be discharged completely from the cap, but may remain in the cap, due to the structure of the cap.
If the ink remains in the cap, the ink may leak into the ink-jet printer, or solidify in the cap or on the edges, which prevents the cap from covering the ejection surface tightly. If the cap is used to cover the ejection surface when recording is not performed, the ink remaining in the cap may be attached to the ejection surface when the cap covers the ejection surface. Such an attachment of ink to the ejection surface causes, for example, the ink to be ejected in a direction shifted or varied from a predetermined direction, resulting in an ink ejection failure.
To solve the above-described problems, an ink-jet recording apparatus is disclosed in Japanese Patent No. 2806611. In Japanese Patent No. 2806611, the cap has a 0.4 mm to 0.7 mm-wide groove at a bottom wall of a recess of a cap which defines a space or room with the print head ejection surface when the cap covers the ejection surface. The ink is collected in the groove and the collected ink is discharged from the cap through a suction opening formed in the bottom wall of the recess.
However, when the cap having the groove at the bottom wall of the recess thereof is formed by molding, the groove is required to have a certain width, to prevent a mold for the cap from breaking where the groove is formed. Accordingly, a cap having a narrow groove is difficult to form by molding. Therefore, the groove is, in reality, formed with an unnarrow, or wide, width. However, the groove with a wide width does not lead the ink in the cap completely to the suction opening, so that the ink is likely to remain in the cap. If the cap is formed by cutting, manufacturing processes for the cap become complicated, resulting in an increase in cost so as to become impractical.
To solve the above-described drawbacks, the invention provides an ink-jet recording apparatus including a cap that is formed with a simple structure and does not leave ink in the cap.
An ink-jet recording apparatus according to the invention may include a recording head including an ejection surface and at least one nozzle formed thereon for recording onto a recording medium by ejecting ink from the nozzle, a cap device for covering the ejection surface of the recording head, and a suction device connected to the suction opening formed in the recess of the cap device and able to suck the ink through the nozzle and discharge the sucked ink from the cap device through a suction opening.
The cap device may include a cap member and a capillary force generating member. The cap member includes a contact portion able to be in contact with the ejection surface and a recess forming a room with the ejection surface of the recording head when the cap member contacts the ejection surface of the recording head, the suction opening communicating with the recess through which ink is sucked. The capillary force generating member may be separately formed from the cap member. The capillary force generating member may be disposed in the cap member to form spaces with a inner surface of the recess of the cap member so that capillary force is generated toward a part of the inner surface of the recess where the suction opening is formed.
In the ink-jet recording apparatus having the above-described structure, as the suction device sucks the ink from the nozzles when the cap member of the cap device contacts the ejection surface of the recording head, the ink is received in the recess of the cap member. By disposing the capillary force generating member in the recess, spaces are formed between the capillary force generating member and the inner surface of the recess. In the spaces a capillary force is generated toward a part of the inner surface of the recess where the suction opening is formed. Therefore, the ink in the recess can be discharged smoothly outside the cap device, through the suction opening, without being left in the recess, by a suction force applied by the suction device.
Because the ink does not remain in the cap device, problems such that the ink-jet printing apparatus is contaminated with the ink remaining in the cap device or the occurrence of an ink ejection failure can be prevented. Therefore, an ink-jet recording apparatus that maintains high print quality can be provided.